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Much of Canada's terrestrial biodiversity is supported by boreal forests. Natural resource development in boreal forests poses risks to this biodiversity. This paper reviews the scientific literature to assess the effects of natural resource development on terrestrial biodiversity in Canadian boreal forests. We address four questions: (1) To what extent have Canadian boreal forests changed due to natural resource development? (2) How has biodiversity responded to these changes? (3) Will the biodiversity of second-growth forests converge with that of primary boreal forests? (4) Are we losing species from boreal forests? We focus on trees, understory plants, insects, fungi, selected mammals, and songbirds because these groups have been most studied. We review more than 600 studies and found that changes in community composition are prevalent in response to large-scale conversion of forest types, changes in stand structures and age distributions, and altered landscape structure resulting from forest management and habitat loss associated with other developments such as oil and gas, hydroelectric, and mining. The southern boreal forest has been more highly impacted than the north due to more extensive forest management and the cumulative effects of multiple forms of development. There is abundant evidence that most species are not in danger of being extirpated from the boreal forest due to these anthropogenic changes. A few species, including woodland caribou (Rangifer tarandus) and grizzly bear (Ursus arctos), have, however, undergone long-term range contractions. Significant gaps in our ability to assess the effects of natural resource development on biodiversity in the boreal zone are the lack of long-term spatial and population data to monitor the impact of forest changes on ecosystems and species. Key words: terrestrial biodiversity, boreal forest, natural resource development, forest management, forest conversion. Une bonne partie de la biodiversite du Canada se retrouve en foret boreale. Le developpement des ressources naturelles dans des forets boreales presente des risques pour cette biodiversite. Les auteurs presentent une revue de la litterature pour evaluer les effets du developpement des ressources naturelles sur la biodiversite terrestre dans les forets boreales canadiennes. Ils ont souleve quatre questions: (1) jusqu'il quel point les forets boreales canadiennes se sont vues modifiees par le developpement des ressources naturelles ? (2) Comment la biodiversite a-t-elle reagi a ces changements ? (3) Y aura-t-il convergence de la biodiversite des forets de seconde venue avec celle des forets boreales primaires ? (4) Subissons-nous des pertes d'especes en forets boreales ? Les auteurs se sont interesses en particulier aux arbres, aux plantes de sous-bois, aux insectes, aux champignons, a des mammiferes et oiseaux chanteurs selectionnes, car ces groupes ont ete les plus etudies. Ils ont suivi plus de 600 especes et ont constate que les changements de composition prevalent en reaction a des modifications a grande echelle des types forestiers, des changements de la structure, des classes d'age, des modifications aux structures des paysages resultant de l'amenagement forestier, ainsi que des pertes d'habitat associees avec d'autres developpements comme l'huile, le gaz, l'hydroelectricite et les mines. La partie meridionale de la foret boreale a recu plus d'impacts que la partie nordique suite a des amenagements forestiers plus intensifs et aux effets cumulatifs des diverses formes de developpement. Il y a beaucoup de preuves que la plupart des especes ne se retrouvent pas en danger d'extinction en forets boreales sous l'influence de modifications anthropogenes. Quelques especes, incluant le caribou forestier (Rangifer tarandus) et l'ours grizzly (Ursus arctos) ont cependant subi des contractions d'habitat a long terme. On observe des deficiences significatives dans notre capacite a evaluer les effets du developpement des ressources naturelles sur la biodiversite dans la zone boreale, du a l'absence de donnees spatiales et a long terme sur les populations, pour suivre l'impact des modifications forestieres sur les ecosystemes et les especes. [Traduit par la Redaction] Mots-cles: biodiversite terrestre, foret boreale, developpement des ressources naturelles, amenagement forestier, conversion des forets., 1. Introduction Biodiversity, broadly defined as the variety of life and its processes, including genes, species, communities, and ecosystems and the ecological and evolutionary processes that keep them functioning (Noss [...]

Canadian boreal woodlands and forests cover approximately 3.09 x [10.sup.6] k[m.sup.2], located within a larger boreal zone characterized by cool summers and long cold winters. Warming since the 1850s, increases in annual mean temperature of at least 2°C between 2000 and 2050 are highly probable. Annual mean temperatures across the Canadian boreal zone could be 4-5°C warmer than today's by 2100. All aspects of boreal forest ecosystem function are likely to be affected. Further, several potential 'tipping elements'--where exposure to increasing changes in climate may trigger distinct shifts in ecosystem state--can be identified across the Canadian boreal zone. Approximately 40% of the forested area is underlain by permafrost, some of which is already degrading irreversibly, triggering a process of forest decline and re-establishment lasting several decades, while also releasing significant quantities of greenhouse gases that will amplify the future global warming trend. Warmer temperatures coupled with significant changes in the distribution and timing of annual precipitation are likely to cause serious tree-killing droughts in the west; east of the Great Lakes, however, where precipitation is generally nonlimiting, warming coupled with increasing atmospheric carbon dioxide may stimulate higher forest productivity. Large wildfires, which can cause serious economic losses, are expected to become more frequent, but increases in mean annual area burned will be relatively gradual. The most immediate threats could come from endemic forest insect pests that have the potential for population outbreaks in response to relatively small temperature increases. Quantifying the multiple effects of climate change will be challenging, particularly because there are great uncertainties attached to possible interactions among them, as well as with other land-use pressures. Considerable ingenuity will be needed from forest managers and scientists to address the formidable challenges posed by climate change to boreal ecosystems and develop effective strategies to adapt sustainable forest management practices to the impending changes. Key words: boreal forest, climate change, disturbance, feedback, permafrost, drought. Les milieux boises et les forets boreales canadiennes couvrent approximativement 3,09 x [10.sup.6] k[m.sup.2], localises au sein d'une vaste zone boreale caracterisee par des etes frais et de longs hivers froids. Avec le rechauffement en marche depuis les annees 1850, des augmentations de la temperature annuelle moyenne d'au moins 2 °C entre 2000 et 2050 apparaissent comme tres probables, et les temperatures moyennes sur l'ensemble de la zone boreale canadienne pourraient s'averer de 4-5 °C plus chaudes que les presentes vers 2100. Tous les aspects du fonctionnement des ecosystemes de la foret boreale sont susceptibles d'etre affectes. De plus, on peut identifier sur l'ensemble de la zone boreale canadienne des 'elements declencheurs' ou l'exposition a des changements accrus du climat peut provoquer des modifications de l'etat des ecosystemes. Environ 40 % des surfaces forestieres vivent sur le pergelisol, dont certaines connaissent presentement une degradation irreversible, enclenchant un processus de declin forestier et de retablissement qui s'etend sur plusieurs decennies, tout en relachant des quantites significatives de gaz a effet serre amplifiant la tendance du rechauffement global. Des temperatures plus chaudes couplees a des changements significatifs de la distribution spatio-temporelle de la precipitation causeront vraisemblablement des secheresses destructrices pour les arbres dans l'ouest; cependant, a l'est des Grands Lacs, ou la precipitation est generalement non limitative, le rechauffement couple a une augmentation du C[O.sub.2] pourrait favoriser une plus forte productivite forestiere. On peut s'attendre a ce que de vastes incendies de foret pouvant causer des pertes economiques enormes deviennent plus frequents, mais les augmentations annuelles moyennes des surfaces brulees se feront relativement graduellement. La menace la plus immediate pourrait venir d'insectes forestiers ravageurs ayant la capacite de connaitre des epidemies en reaction a des augmentations relativement faibles des temperatures. La quantification des multiples effets du changement climatique presente un defi, surtout compte tenu des grandes incertitudes sur les interactions possibles entre elles, aussi bien qu'avec les autres pressions venant de l'utilisation des terres. Il faudra beaucoup d'ingeniosite de la part des amenagistes et des scientifiques pour rencontrer les formidables defis poses par le changement climatique dans les ecosystemes boreaux et pour developper des strategies efficaces afin d'adapter des pratiques d'amenagement forestier durables aux changements imminents. [Traduit par la Redaction] Mots-cles: foret boreale, changement climatique, perturbation, reaction, pergelisol, secheresse., 1. Introduction The Intergovernmental Panel on Climate Change (IPCC 2007) provides a large consensus of scientific expertise that the global climate is now warming. This trend is primarily due to [...]

The boreal zone and its ecosystems provide numerous provisioning, regulating, cultural, and supporting services. Because of its resources and its hydroelectric potential, Canada's boreal zone is important to the country's resource-based economy. The region presently occupied by Canada's boreal zone has experienced dramatic changes during the past 3 million years as the climate cooled and repeated glaciations affected both the biota and the landscape. For about the past 7000 years, climate, fire, insects, diseases, and their interactions have been the most important natural drivers of boreal ecosystem dynamics, including rejuvenation, biogeochemical cycling, maintenance of productivity, and landscape variability. Layered upon natural drivers are changes increasingly caused by people and development and those related to human-caused climate change. Effects of these agents vary spatially and temporally, and, as global population increases, the demands and impacts on ecosystems will likely increase. Understanding how humans directly affect terrestrial and aquatic ecosystems in Canada's boreal zone and how these effects and actions interact with natural disturbance agents is a prerequisite for informed and adaptive decisions about management of natural resources, while maintaining the economy and environment upon which humans depend. This paper reports on the genesis and present condition of the boreal zone and its ecosystems and sets the context for a detailed scientific investigation in subsequent papers published in this journal on several key aspects: carbon in boreal forests; climate change consequences, adaptation, and mitigation; nutrient and elemental cycling; protected areas; status, impacts, and risks of non-native species; factors affecting sustainable timber harvest levels; terrestrial and aquatic biodiversity; and water and wetland resources. Key words: boreal forest, resource development, disturbances, climate change, ecosystem integrity, resilience. La zone boreale et ses ecosystemes fournissent de nombreux services d'approvisionnement, de regularisation, culturels et de support. Compte tenu de ses ressources et de son potentiel hydroelectrique, la zone boreale du Canada est importante pour son economie basee sur les ressources. La region presentement occupee par la zone boreale canadienne a connu des changements drastiques au cours des derniers 3 millions d'annees; un rafraichissement du climat et des glaciations repetees ont affecte a la fois le biote et le paysage. Au cours des 7000 dernieres annees, le climat, le feu, les insectes, les maladies et leurs interactions ont constitue les forces naturelles les plus importantes derriere la dynamique des ecosystemes boreaux, incluant la rajeunissement, le cyclage biogeochimique, le maintien de la productivite et la variabilite des paysages. Se superposant aux agents naturels, il y a les changements causes par les habitants et le developpement ainsi que ceux relies au changement climatique d'origine anthropique. Les effets de ces agents varient de facon spatio-temporelle et a mesure que la population globale augmente, les demandes et les impacts sur les ecosystemes sont susceptibles d'augmenter. La comprehension de la facon avec laquelle les humains affectent directement les ecosystemes terrestres et aquatiques de la zone boreale du Canada et comment ces effets et ces activites interagissent avec les agents de perturbations naturelles constituent un prealable pour la prise de decisions documentees et adaptatives en amenagement des ressources naturelles, tout en maintenant l'economie et l'environnement dont dependent les humains. On fait ici etat de la genese et de la condition actuelle de la zone boreale et de ses ecosystemes et etablit le contexte pour une recherche scientifique detaillee, presentee dans les autres sujets traites dans ce journal sur plusieurs aspects; carbone dans la foret boreale; consequences, mitigation adaptation au changement climatique; cyclage des nutriments et des elements; aires protegees; etat, impacts et risques des especes adventices; etats et moteurs des niveaux de recolte durable; biodiversite terrestre et aquatique; et ressources en eau et terres humides. [Traduit par la Redaction] Mots-cles: foret boreale, developpement des ressources, perturbations, changement climatique, integrite des ecosystemes, resilience., 1. Introduction Large areas of the world are subject to overpopulation, disasters, air and water pollution, loss of biological diversity, deforestation, and soil degradation and depletion (Vitousek et al. 1997; [...]

Much of Canada's terrestrial biodiversity is supported by boreal forests. Natural resource development in boreal forests poses risks to this biodiversity. This paper reviews the scientific literature to assess the effects of natural resource development on terrestrial biodiversity in Canadian boreal forests. We address four questions: (1) To what extent have Canadian boreal forests changed due to natural resource development? (2) How has biodiversity responded to these changes? (3) Will the biodiversity of second-growth forests converge with that of primary boreal forests? (4) Are we losing species from boreal forests? We focus on trees, understory plants, insects, fungi, selected mammals, and songbirds because these groups have been most studied. We review more than 600 studies and found that changes in community composition are prevalent in response to large-scale conversion of forest types, changes in stand structures and age distributions, and altered landscape structure resulting from forest management and habitat loss associated with other developments such as oil and gas, hydroelectric, and mining. The southern boreal forest has been more highly impacted than the north due to more extensive forest management and the cumulative effects of multiple forms of development. There is abundant evidence that most species are not in danger of being extirpated from the boreal forest due to these anthropogenic changes. A few species, including woodland caribou ( Rangifer tarandus) and grizzly bear ( Ursus arctos), have, however, undergone long-term range contractions. Significant gaps in our ability to assess the effects of natural resource development on biodiversity in the boreal zone are the lack of long-term spatial and population data to monitor the impact of forest changes on ecosystems and species. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Reviews is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Environmental Reviews is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Environmental Reviews is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The boreal zone and its ecosystems provide numerous provisioning, regulating, cultural, and supporting services. Because of its resources and its hydroelectric potential, Canada's boreal zone is important to the country's resource-based economy. The region presently occupied by Canada's boreal zone has experienced dramatic changes during the past 3 million years as the climate cooled and repeated glaciations affected both the biota and the landscape. For about the past 7000 years, climate, fire, insects, diseases, and their interactions have been the most important natural drivers of boreal ecosystem dynamics, including rejuvenation, biogeochemical cycling, maintenance of productivity, and landscape variability. Layered upon natural drivers are changes increasingly caused by people and development and those related to human-caused climate change. Effects of these agents vary spatially and temporally, and, as global population increases, the demands and impacts on ecosystems will likely increase. Understanding how humans directly affect terrestrial and aquatic ecosystems in Canada's boreal zone and how these effects and actions interact with natural disturbance agents is a prerequisite for informed and adaptive decisions about management of natural resources, while maintaining the economy and environment upon which humans depend. This paper reports on the genesis and present condition of the boreal zone and its ecosystems and sets the context for a detailed scientific investigation in subsequent papers published in this journal on several key aspects: carbon in boreal forests; climate change consequences, adaptation, and mitigation; nutrient and elemental cycling; protected areas; status, impacts, and risks of non-native species; factors affecting sustainable timber harvest levels; terrestrial and aquatic biodiversity; and water and wetland resources. [ABSTRACT FROM AUTHOR]

Canadian boreal woodlands and forests cover approximately 3.09 × 106 km2, located within a larger boreal zone characterized by cool summers and long cold winters. Warming since the 1850s, increases in annual mean temperature of at least 2 °C between 2000 and 2050 are highly probable. Annual mean temperatures across the Canadian boreal zone could be 4-5 °C warmer than today's by 2100. All aspects of boreal forest ecosystem function are likely to be affected. Further, several potential 'tipping elements' - where exposure to increasing changes in climate may trigger distinct shifts in ecosystem state - can be identified across the Canadian boreal zone. Approximately 40% of the forested area is underlain by permafrost, some of which is already degrading irreversibly, triggering a process of forest decline and re-establishment lasting several decades, while also releasing significant quantities of greenhouse gases that will amplify the future global warming trend. Warmer temperatures coupled with significant changes in the distribution and timing of annual precipitation are likely to cause serious tree-killing droughts in the west; east of the Great Lakes, however, where precipitation is generally nonlimiting, warming coupled with increasing atmospheric carbon dioxide may stimulate higher forest productivity. Large wildfires, which can cause serious economic losses, are expected to become more frequent, but increases in mean annual area burned will be relatively gradual. The most immediate threats could come from endemic forest insect pests that have the potential for population outbreaks in response to relatively small temperature increases. Quantifying the multiple effects of climate change will be challenging, particularly because there are great uncertainties attached to possible interactions among them, as well as with other land-use pressures. Considerable ingenuity will be needed from forest managers and scientists to address the formidable challenges posed by climate change to boreal ecosystems and develop effective strategies to adapt sustainable forest management practices to the impending changes. [ABSTRACT FROM AUTHOR]